Space & Innovation

Women's Natural Scent More Seductive Than Perfume

Research shows a link between testosterone levels and a scented stimulus.

Women looking for that special someone might want to think twice before spritzing Chanel No. 5. A new study suggests that a woman's natural scent may be all she needs.

Recent research shows that a man's testosterone levels, which are linked with sexual interest, are significantly higher when they smell the shirt of a woman who is ovulating. These findings could lead to the development of new fragrances that mimic this effect, and answer basic questions about human biology.

"This is an issue that has been hotly debated: whether or not ovulation is concealed in human females," said Jon Maner, a co-author of the recent paper in Psychological Science. "In lots of other species, there are very obvious indicators, but it has long been assumed that human females didn't give off these cues."

Over the last 10 years, however, psychologists have found that ovulating women may behave differently, with a tendency to be more flirtatious, have sexual fantasies more frequently, and prefer hyper-masculine men.

In surveys, men report being more attracted to ovulating women. The new study builds on this research by measuring the response of men to a specific chemical cue.

The researchers performed two separate but related experiments. In the first scenario, the scientists gave four women plain, white T-shirts. The women wore the shirts over three days when they went to sleep. The researchers then collected the shirts in plastic bags, divided them up according to whether the woman was ovulating, and froze them.

In the second experiment, the scientists added an extra variable: fresh T-shirts that hadn't been worn by anyone.

T-shirts in hand, the scientists asked dozens of men to stick their noses into the bags. As the men sniffed the shirts, scientists sampled the participants' saliva, which was used to measure testosterone.

Men who smelled the shirts of ovulating women in the first experiment had, on average, testosterone levels that were 37 percent higher than the men who smelled the shirts of non-ovulating women.

For the second experiment, the testosterone levels of the men who smelled the T-shirts of ovulating women were, on average, 15 percent higher than men who sniffed the two other T-shirt samples.

Other studies have linked higher levels of testosterone with an increased in sexual arousal, said Maner. Whether a 37 percent or 15 percent difference in testosterone is enough to affect a man's behavior is unknown.

Another unknown is the whether a man could detect an ovulating women in a real-world situation, say a crowded bar. The two experiments were done under controlled laboratory conditions. Nevertheless, scientists say the experiments could have real world significance for potential love connections.

"The men were smelling T-shirts, not real women," said Maner. "We would expect that the odor coming from a woman will be stronger than from a T-shirt that was frozen."

Exactly how far the odor diffuses away from a woman remains to be seen. Scientists also haven't identified the specific chemical scents that stimulate increases in testosterone levels in men.

It's possible that men are directly detecting the higher levels of estrogen during ovulation, said Jim Roney, a scientist at the University of California, Santa Barbara. Equally possible is that men are sensing other chemicals that rise and fall depending on the amount of estrogen. Scientists just don't know.

Despite the remaining unknowns, the new research marks a milestone for smell scientists.

"This is one of the first papers to show (a change in testosterone) in response to a chemical stimulus," said Roney. "It's a new area of research."

For the second experiment, the testosterone levels of the men who smelled the T-shirts of ovulating women were, on average, 15 percent higher than men who sniffed the two other T-shirt samples.

Other studies have linked higher levels of testosterone with an increased in sexual arousal, said Maner. Whether a 37 percent or 15 percent difference in testosterone is enough to affect a man's behavior is unknown.

Another unknown is the whether a man could detect an ovulating women in a real-world situation, say a crowded bar. The two experiments were done under controlled laboratory conditions. Nevertheless, scientists say the experiments could have real world significance for potential love connections.

"The men were smelling T-shirts, not real women," said Maner. "We would expect that the odor coming from a woman will be stronger than from a T-shirt that was frozen."

Exactly how far the odor diffuses away from a woman remains to be seen. Scientists also haven't identified the specific chemical scents that stimulate increases in testosterone levels in men.

It's possible that men are directly detecting the higher levels of estrogen during ovulation, said Jim Roney, a scientist at the University of California, Santa Barbara. Equally possible is that men are sensing other chemicals that rise and fall depending on the amount of estrogen. Scientists just don't know.

Despite the remaining unknowns, the new research marks a milestone for smell scientists.

"This is one of the first papers to show (a change in testosterone) in response to a chemical stimulus," said Roney. "It's a new area of research."

Men appear to be unconsciously aware of when a woman is most fertile.

Ever since 1890, when the use of anesthetics and antiseptics made it unlikely for people to die getting a nose job, cosmetic plastic surgery has been part of the global culture. By the 1920s, plastic surgery grew ever more common, and became associated with vanity. New techniques developed during World War II helped further increase demand for -- and types of -- the elective surgeries.

The era of minimally-invasive techniques has marked a new generation of plastic surgery options, with 14.6 million cosmetic procedures performed in the United States in 2012, up 5 percent since 2011. Here are the current most popular cosmetic surgeries, according to the American Society of Plastic Surgeons.

Initially, cosmetic plastic surgery was not seen as a vanity procedure, said Emory University professor Sander Gilman, author of Making the Body Beautiful: A Cultural History of Aesthetic Surgery.

"Jews in Germany had their noses reduced so they could get jobs," Gilman said. As such, it was equally common for men and women to undergo plastic surgery.

"By the end of the 19th century there's a common understanding in the West that you can transform yourself, you can move classes -- and you can get a new nose," Gilman said.

Ear pinbacks were also popular at the time, to correct "prominent ears."

By the 1920s, the world of cosmetic surgery had shifted. By then, the first textbook about facial cosmetic surgery was in circulation, called "The Correction of Featural Imperfections" by Charles Miller. Women sought face lifts for reasons associated with vanity, not employment.

"It becomes something we associate with the upper middle class," Gilman said.

Everything from ivory to rubber has been used to augment breasts since the beginning of the 20th century. Nothing worked well (one of the first experimental substances, paraffin, had particularly bad results, with breasts that grew hard and lumpy and high rates of infection) until the Dow Corning Corporation developed the first silicone breast implants in 1961. Even though breast augmentation dropped 7 percent from 2011, it's still the No. 1. plastic surgery in the U.S., with 286,000 procedures in the U.S. in 2012. (It's followed by nose reshaping, eyelid surgery, liposuction, and facelifts.)

"People who have had significant weight loss are coming to grips with dealing with [their bodies]," said surgeon David Reath, a member of the American Society of Plastic Surgeons. "Whether they've lost weight through weight reduction surgery or diet and exercise, if they were overweight for a long period, the

skin hangs around, and it’s very demoralizing. They're looking for a solution."

One solution appears to be a procedure called an upper arm lift, which involves either liposuction or brachioplasty, a surgery that removes loose skin is removed from the back of the arms.

Plus, "anytime we start talking about arms the image of the buff First Lady comes into mind," Reath said.

"This is up in every age group of men," Reath said. "I think it's because there’s a growing awareness that there is a solution to something that's extra troubling to men of all ages. It can have a tremendous psychological effect on young men going through puberty."

In fact, the number of men having cosmetic procedures in general has increased so dramatically that Gilman thinks it will once again even out to match the rate of women who undergo plastic surgery.

New minimally invasive and cheaper procedures such as Botox and other injectable fillers took off when the economy took a downturn, Reath said.

"You could take less time off from work [to recover]; year after year it has continued to grow," he said.

In fact, the popularity of such procedures is growing so fast that Gilman believes there will come a point in the next 10 years or so where people will wonder why you didn't have a cosmetic procedure if you have sagging skin under your jaw or lines around your eyes.

"It's becoming the standard," he said.